<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
    /* inline,
       block,
       line-block  */
    img{
        display: block;
    }
    .hide{
        display: none;
    }
     .box:hover ul{ /*鼠标移上去显示 */
        /* background-color: yellow; */
        display: block;
    }
    </style>
</head>
<body>
    <img src="touxiang.png" alt="">
    <p>1111111111111111111111</p>

    <div class="hide">11111111111111111</div>
    <div class="box">
        军事
        <ul class="hide">
            <li>1111</li>
            <li>1111</li>
            <li>1111</li>
        </ul>
    </div>
</body>
</html>